How much dry ice do I need is a very common question. Rest assured that it does not have a very straight forward answer. There are a lot of variables that play here, freezer, fridge, or cooler, what size is it, how much food is in it, how long do you need to keep the food for, etc. Although I can’t depict every possible scenario, I will try to come up with something that should help the majority of people.
In the refrigerator, place dry ice block on bottom shelf away from any food. If the dry ice is near the food, it may cause the food to freeze.
Do not place dry ice directly on the shelf or against the cooler, instead use newspaper underneath it. Dry ice could cause the shelf to crack if it is placed directly on it. Some people wrap the entire block of dry ice in newspaper.
Keep an eye on the block, as it will sublimate away. Replace the dry ice when needed.
Do not touch the dry ice, it could burn you. Instead use gloves and/or tongs. It is best to know all the safety precautions before using dry ice.
In the cooler, make sure it has proper ventilation. As the dry ice sublimates, it could cause pressure to build up.
Dry ice can carbonate beverages. Any beverage that does not have an air tight seal will get carbonated.
NOTE: These are estimates and may vary based on many conditions.
In the refrigerator:
Refrigerator - 10-15 lbs of dry ice per day (24 hours).
In the freezer:
Freezer below refrigerator – 20-25 lbs of dry ice per day (24 hours)
Freezer above refrigerator - 25-30 lbs of dry ice per day (24 hours)
Freezer side by side refrigerator - 35-40 lbs of dry ice per day (24 hours)
Freezer chest or full size upright freezer - 45-50 lbs of dry ice per day (24 hours)
In a cooler:
Standard plastic cooler - 7-9 lbs of dry ice per day (24 hours)